textproduct: Albany

WHAT HAS CHANGED

No significant changes to the forecast.

KEY MESSAGES

1) While temperatures will trend warmer through the end of the week, impactful heat is not expected as humidity levels remain low.

2) Showers and thunderstorms are likely this weekend with a chance for heavy downpours during any thunderstorm. There is a low chance for strong storms on Saturday.

DISCUSSION

KEY MESSAGE 1...

The ridge from the incoming omega block will build overhead today before starting to flatten out tomorrow. This will maintain our stretch of dry and sunny weather with temperatures trending warmer each day as 850hPa isotherms rise towards +14C to +17C. While sufficiently deep boundary layer mixing will allow temperatures in valley areas to warm well into the 80s to even low 90s, the northwesterly wind direction will keep humidity levels low and thus mitigate the potential for heat impacts. Friday will feature the highest chance (50 to 80%) for temperatures to reach or exceed 90 degrees in valley areas as westerly winds aloft advect in the core of the warm air mass with only cirrus clouds spilling overtop the weakening ridge. While the warm air mass lingers into Saturday, the highest potential for temperatures to reach or exceed 90 degrees shifts to areas mainly from I-90 southward given increasing clouds and chances for showers and thunderstorms. Humidity levels rise slightly on Saturday compared to the previous few days making it feel muggier, especially in the mid-Hudson Valley where there is a low to medium chance for temperatures to reach into the mid-90s; however, heat-related impacts still appear unlikely with the latest HeatRisk only showing widespread moderate (2 of 4) levels. Typically, Major HeatRisk (level 3 of 4) raises concerns for heat impacts.

KEY MESSAGE 2...

Our ridge flattens out over the Northeast by Saturday with a shortwave trough approaching from the Great Lakes. Increasing height falls spread into eastern NY and western New England from northwest to southeast through the day with a pre-frontal trough on the leading edge of the height falls provide a focus for surface based convection. Zonal flow aloft advecting increased moisture into the region will likely support mostly cloudy skies and thus limit overall instability. Latest probabilistic guidance generally shows less than a 40% chance for surface based CAPE values to reach or exceed 1000 J/kg. The highest values remain south of I-90 where showers and storms look to hold off until Saturday afternoon and where there is the highest chance for enough insolation to help generate instability. Despite overall low instability, stregthening flow aloft will contribute to higher deep layer shear values ranging 25-35kts. Depending on how much instability can develop, the higher shear values may be sufficient to support some organized convection but the potential for strong storms remains low given instability uncertainty. Forecast soundings show a classic "tall, skinny CAPE" signature and with PWATs rising nearly 2 standard deviations above normal and warm cloud depths greater than 10kft, efficient warm rain processes should support potential for heavy downpours during any storm. Still some uncertainty on when the pre-frontal trough arrives but initial showers/storms look to reach areas north and west of I-90 first either Saturday morning or early afternoon before sliding south and east Saturday afternoon.

Chance and likely POPs for scattered areas of showers and storms continue Saturday night and Sunday as the parent trough finally moves overhead. However, a strengthening area of high pressure from Canada quickly builds southward Sunday afternoon into Monday, kicking the parent trough to our south and supporting a drying and cooling trend. Seasonably cool and comfortable conditions last through Monday before a warming trend returns for the middle to end of next week.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Through 12z/Friday...As of 6:50am, VFR conditions prevail across all the terminals and are expected to continue through the entire 24 hour TAF period. Calm winds this morning begin to increase by late morning becoming 5-10 kt from the southwest/west by the afternoon with isolated gusts around 15-20 kt especially at KALB and KPSF. Winds then taper off after sunset.

Outlook...

Friday Night: No Operational Impact. NO SIG WX. Saturday: High Operational Impact. Definite SHRA...TSRA. Saturday Night: High Operational Impact. Likely SHRA...TSRA. Sunday: High Operational Impact. Definite SHRA...TSRA. Sunday Night: Low Operational Impact. Slight Chance of SHRA. Monday: No Operational Impact. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.